The present disclosure relates to a dusting method, for example for the moist cleaning of motor vehicle body components before painting.
Furthermore, the present disclosure relates to a corresponding dusting device which is suitable for the moist cleaning of motor vehicle body components and has a sword brush as a dusting tool, for example.
In painting installations for motor vehicle body components, the motor vehicle body components must generally be dusted before painting the components. In some examples so-called sword brushes can be used for dusting the components, for example as described generally in DE 43 14 046 A1 and DE 103 29 499 B3. The sword brush is typically mounted on a hand wrist of a multi-axis robot and is guided by the robot over the surfaces to be dusted of the motor vehicle body components to be painted. In some examples, the sword brush dedusts the surfaces to be dusted using moisture.
One disadvantage of using sword brushes for dusting motor vehicle body components is the generally low tolerance of sword brushes with regards to a penetration depth relative to a surface being dusted. On the one hand, the cleaning brushes attached on the rotating brush belt of the sword brush must touch the surfaces to be dusted, in order to remove dust from the surfaces. On the other hand, a certain spacing between the rotating dusting belt of the sword brush and the surface to be dusted should generally not fall below a predetermined minimum distance, as the dusting brushes are generally deformed to a greater extent with increasing penetration depth, which can lead to damage to the cleaning brushes and, in the worst case, to a collision between the sword brush or hard components thereof and the component to be dusted.
Furthermore, the cleaning result using a sword brush is generally dependent on the penetration, wherein an optimal cleaning result can only be achieved if the penetration depth remains within a certain predetermined range.
The generally low positioning tolerance of known sword brushes is problematic in particular because the positioning of the motor vehicle body components to be dusted in a painting installation is only possible with a relatively low positioning accuracy, which must be accommodated by the sword brush.
One reason for the low positioning accuracy of the motor vehicle body components to be dusted consists in the fact that the motor vehicle body components themselves can have tolerances in terms of their dimensions of up to a centimeter (1 cm), which cannot be changed.
A further reason for the low positioning accuracy of the motor vehicle body components to be dusted is that the conveying technology used to transport motor vehicle bodies or components thereof is itself subject to tolerances, which may only be changed with great difficulty and or large investment in the conveying technology.
Finally, another reason for the low positioning accuracy of the motor vehicle body components to be dusted is that the motor vehicle body components are transported by a skid that is also subject to positioning tolerances.
The tolerance deviations in the case of the positioning of the motor vehicle body components to be dusted therefore often exceed the tolerance compensation abilities of the sword brush, and periodically lead to a production stop caused by the triggering of collision protection, e.g., between sword brushes and a motor vehicle body component.
An aircraft washing installation is disclosed by Klaus Dieter Rupp: “Zur Fehlerkompensation and Bahnkorrektur für eine mobile Grolβmanipulator-Anwendung”, Springer-Verlag (1996), in the case of which aircraft washing installation, a washing brush is guided by a large manipulator over the aircraft surfaces to be washed. Here also, the penetration depth of the washing brush must be kept within a certain tolerance in order to avoid a collision between the washing brush and the aircraft to be cleaned on the one hand and to achieve a good washing action on the other hand. This publication generally controls the penetration depth of the washing brush as a function of the torque of a washing brush motor. So, the torque of the washing brush motor likewise increases with increasing penetration depth, as the brushes of the washing brush are deformed to a greater extent with increasing penetration depth. The torque of the washing brush motor is therefore a measure for the penetration depth and can therefore be used as a measurement variable.
This known controlling of the penetration depth as a function of the torque of the drive motor has not been applied to sword brushes for various reasons.
On the one hand, the tolerance field of the penetration depth is significantly smaller in the case of sword brushes than in the case of the previously mentioned large washing installations for aircraft.
On the other hand, sword brushes are not only used for dusting planar surfaces typical of the larger aircraft applications, but rather are also used for the dusting of curved surfaces. It has been shown however that the driving torque of the sword brush motor alone is generally not a suitable measure for the penetration depth if curved surfaces are dusted.
Finally, cleaning devices for large objects such as aircraft and/or ships are known from U.S. Pat. No. 5,525,027, DE 44 28 069 A1 and DE 44 33 925 A1, in the case of which cleaning devices, the contact pressure of a cleaning brush is measured and controlled. These cleaning devices are not dusting devices in the sense according to the invention, however. Furthermore, these cleaning devices are not suitable for cleaning motor vehicle body components in a painting installation.